1. Field of the Invention
The present invention relates to keyboard apparatuses, such as, for example, small size and portable electronic organs, electronic keyboard apparatuses and the like.
2. Description of Related Art
A conventional electronic keyboard musical instrument typically has a case (a housing) that is made with a resin. Generally, a keyboard apparatus is independently assembled and then mounted within the case. For example, Japanese Utility Model publication HEI 7-15019 and Japanese Patent publication HEI 6-31939 describe portable type electronic keyboard musical instruments having the conventional structure. The keyboard apparatus generally includes a keyboard chassis (or a frame) that is formed from metal plates or reinforced plastic and a plurality of keys (white keys and black keys) that are movably supported over the keyboard chassis and successively arranged in a predetermined direction. The keyboard apparatus further includes a key switch, a key returning force application device, a key guide, an upper limit stopper for limiting the upper-most ascending position of the key and a lower limit stopper for limiting the lower-most ascending position provided for each of the keys.
For example, Japanese Patent Publication HEI 6-31939 describes a portable type electronic keyboard musical instrument having a keyboard chassis of a relatively complicates structure. The keyboard chassis is mounted within an instrument housing that is forme from an upper casing and a lower casing. The keyboard chassis of Japanese Patent Publication HEI 6-31939 has numerous key guide aperture sections or &lt;lit sections that guide and stop associated keys which are movable between an initial position and a depressed position. More specifically, each of the keys has a vertically extending section that is inserted through an associated one of the key guide aperature sections. The vertically extending section includes a hook section that engages an edge section of the key guide aperture section to retain the key in a predetermined position when the key returns to its initial position. The structure of the key guide aperture sections is relatively complicated and difficult to form by a resin.
In this manner, the conventional keyboard musical instrument described above contains a relatively large number of parts, the structure of the instrument is complicated and relatively many assembling steps are required. As a result, the cost of the musical instrument is increased.